Systems and methods for low-manganese welding alloys

ABSTRACT

Systems and methods for low-manganese welding alloys are disclosed. An example arc welding consumable may comprise: less than 0.4 wt % manganese; strengthening agents selected from the group consisting of nickel, cobalt, copper, carbon, molybdenum, chromium, vanadium, silicon, and boron; and grain control agents selected from the group consisting of niobium, tantalum, titanium, zirconium, and boron. The grain control agents may comprise greater than 0.06 wt % and less than 0.6 wt % of the welding consumable. The resulting weld deposit may comprise a tensile strength greater than or equal to 70 ksi, a yield strength greater than or equal to 58 ksi, a ductility (as measured by percent elongation) of at least 22%, and a Charpy V-notch toughness greater than or equal to 20 ft-lbs at −20° F. The welding consumable may provide a manganese fume generation rate less than 0.01 grams per minute during the arc welding operation.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/847,282, filed Dec. 19, 2017, which is a continuation of U.S. patentapplication Ser. No. 14/457,599, filed Aug. 12, 2014, now U.S. Pat. No.9,844,838, which is a continuation-in-part of U.S. patent applicationSer. No. 14/265,750, filed Apr. 30, 2014, now U.S. Pat. No. 9,895,774,which claims priority to U.S. Provisional Patent Application Ser. No.61/821,064, entitled filed May 8, 2013. The entireties of U.S. patentapplication Ser. Nos. 15/847,282, 14/457,599, 14/265,750, and61/821,064, each entitled, “SYSTEMS AND METHODS FOR LOW-MANGANESEWELDING ELECTRODES,” are incorporated herein by reference.

BACKGROUND

The present disclosure relates generally to welding alloys and, morespecifically, to welding consumables (e.g., welding wires and rods) forwelding, such as Gas Metal Arc Welding (GMAW), Gas Tungsten Arc Welding(GTAW), Shielded Metal Arc Welding (SMAW), and Flux Core Arc Welding(FCAW).

Welding is a process that has become ubiquitous in various industriesfor a variety of applications. For example, welding is often used inapplications such as shipbuilding, offshore platform, construction, pipemills, and so forth. Certain welding techniques (e.g., Gas Metal ArcWelding (GMAW), Gas-shielded Flux Core Arc Welding (FCAW-G),Self-shielded Flux Core Arc Welding (FCAW-S), and Submerged Arc Welding(SAW)), typically employ a welding consumable in the form of weldingwire. Other welding techniques (e.g., Shielded Metal Arc Welding (SMAW)and Gas Tungsten Arc Welding (GTAW)) may utilize a welding consumable inthe form of a stick or rod. These types of welding consumables maygenerally provide a supply of filler metal to form the weld deposits ona workpiece.

BRIEF DESCRIPTION

In an embodiment, a welding consumable includes less than approximately1 wt % manganese, as well as one or more strengthening agents selectedfrom the group: nickel, cobalt, copper, carbon, molybdenum, chromium,vanadium, silicon, and boron. Additionally, the welding consumable has acarbon equivalence (CE) value that is less than approximately 0.23. Thewelding consumable also includes one or more grain control agentsselected from the group: niobium, tantalum, titanium, zirconium, andboron, wherein the welding consumable includes less than approximately0.6 wt % grain control agents. The welding consumable is designed toprovide a manganese fume generation rate of less than approximately 0.01grams per minute during a welding operation.

In another embodiment, a method of forming a weld deposit during awelding operation includes advancing a welding consumable toward astructural steel workpiece, wherein the welding consumable comprisesless than approximately 1 wt % manganese. The method includesestablishing an arc between a welding electrode and the structural steelworkpiece. The method also includes melting a portion of the weldingconsumable and a portion of the structural steel workpiece to form theweld deposit, wherein the welding operation generates less thanapproximately 0.01 grams of manganese fumes per minute.

In another embodiment, a weld deposit is formed on a steel workpieceusing an arc welding operation and a welding consumable that producesless than approximately 0.01 grams of manganese fumes per minute. Theweld deposit comprises: less than approximately 1 wt % manganese; atensile strength greater than or equal to approximately 70 ksi; a yieldstrength greater than or equal to approximately 58 ksi; a ductility, asmeasured by percent elongation, that is at least approximately 22%; anda Charpy V-notch (CVN) toughness greater than or equal to approximately20 ft-lbs at −20° F.

DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a block diagram of a gas metal arc welding (GMAW) system, inaccordance with embodiments of the present disclosure;

FIG. 2 is a graph illustrating melt-off rate versus welding current fora series of example welding operations using an embodiment of a solidwelding electrode of the present disclosure;

FIG. 3 is a graph illustrating melt-off rate versus wire feed speed forthe series of example welding operations using the solid weldingelectrode embodiment of FIG. 2 ;

FIG. 4 is a graph illustrating percentage of the electrode converted tofumes versus wire feed speed for the series of example weldingoperations using the solid welding electrode embodiment of FIG. 2 ;

FIG. 5 is a graph illustrating welding fume generation rate versus wirefeed speed for the series of example welding operations using the solidwelding electrode embodiment of FIG. 2 ; and

FIG. 6 is a graph illustrating manganese welding fume generation rateversus wire feed speed for the series of example welding operationsusing the solid welding electrode embodiment of FIG. 2 .

DETAILED DESCRIPTION

One or more specific embodiments of the present disclosure will bedescribed below. In an effort to provide a concise description of theseembodiments, all features of an actual implementation may not bedescribed in the specification. It should be appreciated that in thedevelopment of any such actual implementation, as in any engineering ordesign project, numerous implementation-specific decisions must be madeto achieve the developers' specific goals, such as compliance withsystem-related and business-related constraints, which may vary from oneimplementation to another. Moreover, it should be appreciated that sucha development effort might be complex and time consuming, but wouldnevertheless be a routine undertaking of design, fabrication, andmanufacture for those of ordinary skill having the benefit of thisdisclosure.

When introducing elements of various embodiments of the presentdisclosure, the articles “a,” “an,” “the,” and “said” are intended tomean that there are one or more of the elements. The terms “comprising,”“including,” and “having” are intended to be inclusive and mean thatthere may be additional elements other than the listed elements. Itshould be appreciated that, as used herein, the term “tubular weldingelectrode” or “tubular welding wire” may refer to any welding wire orelectrode having a metal sheath and a granular or powdered core, such asmetal-cored or flux-cored welding electrodes. It should be appreciatedthat the term “tubular,” as used herein, may include various shapes ofwelding wire, including round, elliptical, square, polygonal, or anyother suitable shape. It should be appreciated that the phrase“substantially free from/of” with respect to a particular component mayrefer to the particular component being present in only traceconcentrations (e.g., less than approximately 0.01%, less thanapproximately 0.001%, or less than approximately 0.0001%) or beingcompletely absent (e.g., 0 wt % or below a detection limit).

Present embodiments are directed toward alloys for use in weldingapplications (e.g., as welding consumables). For example, presentlydisclosed welding alloys may, in certain embodiments, be formed intosolid welding wires (e.g., for use in GMAW or SAW applications). Incertain embodiments, the disclosed welding alloys may be formed intowire, cut into lengths, and then coated with a flux to form stickelectrodes (e.g., for SMAW applications). In other embodiments, thepresently disclosed alloy may be formed into a sheath of a tubularwelding wire and filled with a granular core material to yield aflux-cored or metal-cored welding wire (e.g., for FCAW-G or FCAW-Sapplications). In certain embodiments, the disclosed welding alloys maybe formed into wires and cut into lengths of rod for use in Gas TungstenArc Welding (GTAW) applications. As such, it may be appreciated that thepresently disclosed alloy may be useful for the production of any numberof welding consumables.

In particular, the presently disclosed welding alloys have a lowmanganese content. More specifically, the disclosed welding alloyembodiments include less than approximately 2 wt % manganese, such asless than approximately 1.5 wt % manganese, less than approximately 1 wt% manganese, less than approximately 0.9 wt % manganese, or even onlyincluding trace manganese content. Accordingly, as set forth in detailbelow, the disclosed welding alloys enable the production of weldingconsumables (e.g., welding wires and rods) that have betweenapproximately 5% and approximately 95% less manganese content than otherwelding consumables, and these welding consumables enable the productionof low-manganese weld deposits and low-manganese welding fumes. Further,the presently disclosed welding alloys are useful for welding structuralsteel (e.g., mild steel, low-alloy steels, carbon steel, or othersuitable structural steel) and non-structural steel (e.g., chrome-molysteel). The presently disclosed welding alloys provide weld depositproperties (e.g., tensile strength, yield strength, etc.) that match orexceed the properties of weld deposits formed using welding consumableshaving substantially higher manganese content. For example, presentembodiments enable the formation of a weld deposit having a manganesecontent less than approximately 2 wt % that provides a suitable tensilestrength (e.g., at least 70 kilopound per square inch (ksi)) as well asa suitable toughness (e.g., a Charpy V-notch (CVN) toughness at least 20ft-lbs at −20° F.), despite the low-manganese content of the welddeposit.

Furthermore, while the presently disclosed welding alloy may be used inthe production of several different types of welding consumables (e.g.,filler rods, stick electrodes, flux-cored wires, metal-cored wires, orsolid electrodes), certain present embodiments are particularly suitedfor forming solid welding wires. It may be appreciated that, in general,solid welding wires produce less welding fumes than flux-cored weldingwires, and generally provide a clean weld deposit that has little or noslag. In contrast, flux-cored welding wires generally form a welddeposit that includes a slag layer that is typically removed after thewelding operation is complete. However, while the removal of the slaglayer formed by flux-cored welding wires may consume more operator timepost-welding, in certain embodiments, this slag layer may advantageouslyserve to remove or reduce the concentration of undesirable elements fromthe weld pool during welding, which may provide greater control over thechemistry of the resulting weld deposit.

As presented below, these weld deposit properties are achieved despitethe low manganese content through the inclusion of one or morestrengthening agents (e.g., nickel, cobalt, copper, carbon, molybdenum,chromium, vanadium, silicon, and/or boron) and one or more grain controlagents (e.g., niobium, tantalum, titanium, zirconium, and/or boron) inthe welding alloy. In other words, it is believed that the addition ofone or more strengthening agents and/or one or more grain control agentsenables satisfactory weld deposit properties to be achieved, in spite ofthe low-manganese levels, when welding steel workpieces (e.g.,structural steel workpieces). Additionally, in certain embodiments, itis believed that including one or more grain control agents (e.g.,niobium, tantalum, titanium, zirconium, and/or boron) in the weldingalloy also compensates for the lower manganese levels such thatsatisfactory mechanical properties (e.g., toughness, tensile strength,etc.) of the weld deposit may be attained, despite the relatively lowmanganese levels, when welding steel workpieces (e.g., structural steelworkpieces). Further, as discussed in detail below, the components(e.g., the one or more strengthening agents) are present in the weldingalloy in suitable relative concentrations such that the welding alloyhas a carbon equivalence value (CE) that is generally less thanapproximately 0.23 (e.g., between approximately 0.07 and approximately0.12).

Welding System

Turning to the figures, FIG. 1 illustrates an embodiment of a gas metalarc welding (GMAW) system 10 that utilizes a welding electrode (e.g.,welding wire or a welding stick or rod) manufactured from a weldingalloy in accordance with the present disclosure. It should beappreciated that while the present discussion may focus specifically onthe GMAW system 10 illustrated in FIG. 1 , the presently disclosedwelding alloy may benefit a number of different welding processes (e.g.,FCAW-S, FCAW-G, GTAW, SAW, or similar welding processes) that use awelding consumable, such as a welding wire or rod. The welding system 10includes a welding power source 12, a welding wire feeder 14, a gassupply system 16, and a welding torch 18. The welding power source 2generally supplies power to the welding system 10 and may be coupled tothe welding wire feeder 14 via a cable bundle 20. The welding powersource 12 may also be coupled to a workpiece 22 using a lead cable 24having a clamp 26. In the illustrated embodiment, the welding wirefeeder 14 is coupled to the welding torch 18 via a cable bundle 28 inorder to supply consumable welding wire (e.g., the welding electrode)and power to the welding torch 18 during operation of the welding system10. In another embodiment, the welding power source 12 may couple anddirectly supply power to the welding torch 18.

The welding power source 12 may generally include power conversioncircuitry that receives input power from an alternating current powersource 30 (e.g., an AC power grid, an engine/generator set, or acombination thereof), conditions the input power, and provides DC or ACoutput power via the cable 20. For example, in certain embodiments, thepower source 30 may be a constant voltage (CV) power source 30. Thewelding power source 12 may power the welding wire feeder 14 that, inturn, powers the welding torch 18, in accordance with demands of thewelding system 10. The lead cable 24 terminating in the clamp 26 couplesthe welding power source 12 to the workpiece 22 to close the circuitbetween the welding power source 12, the workpiece 22, and the weldingtorch 18. The welding power source 12 may include circuit elements(e.g., transformers, rectifiers, switches, and so forth) capable ofconverting the AC input power to a direct current electrode positive(DCEP) output, direct current electrode negative (DCEN) output, DCvariable polarity, pulsed DC, or a variable balance (e.g., balanced orunbalanced) AC output, as dictated by the demands of the welding system10. It should be appreciated that the presently disclosed welding alloymay enable improvements to the welding process (e.g., improved arcstability and/or improved weld quality) for a number of different powerconfigurations.

The illustrated welding system 10 includes a gas supply system 16 thatsupplies a shielding gas or shielding gas mixtures from one or moreshielding gas sources 17 to the welding torch 18. A shielding gas, asused herein, may refer to any gas or mixture of gases (e.g., inert oractive gasses) that may be provided to the arc and/or weld pool in orderto provide a particular local atmosphere (e.g., to shield the arc,improve arc stability, limit the formation of metal oxides, improvewetting of the metal surfaces, alter the chemistry of the weld deposit,and so forth). In the depicted embodiment, the gas supply system 16 isdirectly coupled to the welding torch 18 via a gas conduit 32. Inanother embodiment, the gas supply system 16 may instead be coupled tothe wire feeder 14, and the wire feeder 14 may regulate the flow of gasfrom the gas supply system 16 to the welding torch 18. In otherembodiments, such as certain FCAW-S, SMAW and SAW systems that may notrely on an externally supplied shielding gas, the welding system 10 maynot include the gas supply system 16. For such embodiments, the weldingelectrode may include flux (e.g., a flux core or a flux coating) that atleast partially decomposes near the surface of the workpiece 22 during awelding operation to provide a localized shielding atmosphere.

In certain embodiments, the shielding gas flow may be a shielding gas orshielding gas mixture (e.g., argon (Ar), helium (He), carbon dioxide(CO₂), oxygen (O₂), nitrogen (N₂), hydrogen (H₂), similar suitableshielding gases, or any mixtures thereof). For example, a shielding gasflow (e.g., delivered via the gas conduit 32) may include Ar, CO₂,Ar/CO₂ mixtures (e.g., 75% Ar and 25% CO₂, 90% Ar and 10% CO₂, 95% Arand 5% CO₂, and so forth), Ar/CO₂/O₂ mixtures, Ar/He mixtures, and soforth. Further, it may be appreciated that, as set forth in detailbelow, certain shielding gases (e.g., certain Ar/CO₂ mixtures, such as90% Ar/10% CO₂) may reduce a total amount of welding fumes that may begenerated during the welding operation. For example, in certainembodiments, the shielding gas flow may include between approximately 0%and 100% CO₂, with the remainder of the shielding gas flow being argon,helium, or another suitable gas. In certain embodiments, shielding gasflows including three or more gases (e.g., trimix) are also presentlycontemplated. Additionally, in certain embodiments, the shielding gasmixture may be provided to the arc at a rate of approximately 35 cubicfeet per hour (cfh) to approximately 55 cfh (e.g., approximately 40cfh).

Accordingly, the illustrated welding torch 18 generally receives thewelding wire from the welding wire feeder 14, power from the weldingpower source 12, and a shielding gas flow from the gas supply system 16in order to perform GMAW of the workpiece 22. In certain embodiments,the welding wire feeder 14 may be a constant speed welding wire feeder14. During operation, the welding torch 18 may be brought near theworkpiece 22 so that an arc 34 may be formed between the consumablewelding electrode (i.e., the welding wire exiting a contact tip of thewelding torch 18) and the workpiece 22. Additionally, as discussedbelow, by controlling the composition of the welding wire, the chemicaland mechanical properties of the resulting weld may be varied. Forexample, in certain embodiments, the welding wire may include alloyingcomponents to contribute species (e.g., nickel, molybdenum, silicon,carbon, or other suitable alloying components) to the weld pool,affecting the mechanical properties (e.g., strength and toughness) ofthe weld. Furthermore, certain components of the welding wire may alsoprovide additional shielding atmosphere near the arc, affect thetransfer properties of the arc, clean the surface of the workpiece, andso forth.

Welding Alloy Compositions

As discussed in detail below, the presently disclosed welding alloys mayinclude a number of components. While these components may be groupedinto various categories (e.g., alloying agents, strengthening agents,grain control agents, deoxidizing agents, and so forth), it should beappreciated that certain components may serve multiple roles during thewelding process. As such, it may be appreciated that a disclosure hereinof a particular component serving a particular role does not precludethat component from serving other roles or performing other functionsduring the welding process. For example, as set forth below, in certainembodiments, the disclosed welding alloy may include strengtheningagents (i.e., nickel, cobalt, copper, carbon, molybdenum, chromium,vanadium, silicon, boron, or combinations thereof) and/or grain controlagents (i.e., niobium, tantalum, titanium, zirconium, boron, orcombinations thereof) in order to produce a weld deposit having suitablemechanical properties (e.g., suitable tensile strength and toughness forstructural steel applications).

TABLE 1 Chemical composition for three disclosed classes of weldingalloys, in accordance with embodiments of the present approach. Valuesare listed in terms of weight percent (wt %) relative to the totalweight of the alloy. A1 (wt %) A2 (wt %) A3 (wt %) Carbon 0.001-0.12 0.05-0.07 0.04-0.06 Manganese 0.05-2   0.3-0.4 0.3-0.4 Silicon 0.1-1.20.65-0.85 0.65-0.85 Nickel   0-5.0 0.65-0.85 0.65-0.85 Cobalt 0-20.001-0.7   0.001-0.7   Chromium   0-0.8 0.001-0.2   0.001-0.2  Molybdenum   0-1.5 0.001-0.1   0.001-0.1   Vanadium   0-0.10.0001-0.03   0.0001-0.03   Copper 0.001-2    0.001-0.2   0.1-0.2Titanium 0.01-0.2  0.04-0.16 0.04-0.16 Zirconium 0.01-0.2  0.02-0.1 0.02-0.1  Aluminum 0.001-1    0.05-0.1  0.001-0.01  Niobium   0-0.10.001-0.1   0.001-0.01  Tantalum   0-0.2 0.001-0.2   0.001-0.2   Boron  0-0.01 0.0001-0.001  0.0001-0.001  Antimony   0-0.25    0-0.25   0-0.25 Sulfur   0-0.01 0.001-0.01  0.001-0.01  Phosphorus   0-0.010.001-0.01  0.001-0.01  Iron Balance Balance Balance (~84-99) (~96-98)(~96-98)

With the foregoing in mind, Table 1 presents chemical compositions(i.e., ranges in weight percent) for three classes of welding alloys,A1, A2, and A3, in accordance with embodiments of the present approach.It may be appreciated that the welding alloy A1 defines the broadestranges for the various components and, accordingly, represents thebroadest class of the presently disclosed welding alloy embodiments.Further, welding alloys A2 and A3 represent two subclasses or genusesthat generally fall within the A1 class and, accordingly, define morenarrow ranges for each of the components of the presently disclosedwelding alloy embodiments. While ranges are listed for the components ofthe welding alloy classes A1, A2, and A3 in Table 1, it should beappreciated that the disclosed ranges are not limited to that particularclass, subclass, or embodiment. Indeed, in certain embodiments, anydisclosed component may be included in a welding alloy embodiment of thepresent approach in any disclosed range, or any subranges thereof, inany combination, not just the combinations indicated for classes A1, A2,and A3 of Table 1. For example, a welding alloy embodiment of thepresent approach may include approximately 0 wt % (or only traceamounts) nickel (as set forth for A1 in Table 1), include aluminum in arange between approximately 0.05 wt % and approximately 0.1 wt % (as setforth for A2 in Table 1), and include carbon in a range betweenapproximately 0.04 wt % and approximately 0.06 wt % (as set forth for A3in Table 1). It may be appreciated that, in certain embodiments, each ofthe elements of Table 1 that are present in the welding alloy may onlybe substantially present in metallic or elemental form, meaning that thewelding alloy may be substantially free from salts or compounds (e.g.,oxides, hydroxides, chlorides, etc.) or may only include a small amountof oxides about the outer surface of the welding alloy. Additionally,Table 2 lists the components of two example solid welding wires, E1 andE2, manufactured from embodiments of the presently disclosed weldingalloy. As indicated in Table 2, particular components of the solidwelding wire embodiments E1 and E2 are listed in weight percentagevalues that generally fall within the ranges defined by one or more ofthe classes A1, A2, and A3 set forth in Table 1.

TABLE 2 Chemical composition for two example embodiments of solidwelding wires, E1 and E2, manufactured using welding alloys inaccordance with the present approach. Values are listed in terms ofweight percent (wt %) relative to the total weight of the wire. Valueslisted as “less than” are present at levels that are at or near thelower detection limit for that component. E1 (wt %) E2 (wt %) Carbon0.052 0.05 Manganese 0.39 0.38 Silicon 0.75 0.79 Nickel 0.76 0.77Chromium 0.04 0.01 Molybdenum 0.01 0.01 Vanadium 0.006 <0.001 Copper<0.01 0.15 Titanium 0.11 0.09 Zirconium 0.05 0.06 Aluminum 0.08 0.005Niobium <0.001 <0.01 Boron <0.001 0.0005 Sulfur 0.005 0.01 Phosphorus0.001 0.002 Iron Balance (~98) Balance (~98)

As set forth in Table 1, the presently disclosed welding alloy mayinclude between approximately 0.05 wt % and approximately 2 wt %manganese. It may be appreciated that the presence of manganese maygenerally strengthen the welding alloy. However, as used herein, theterm “strengthening agent” is not meant to encompass manganese, butrather encompasses other components (e.g., nickel, cobalt, copper,carbon, molybdenum, chromium, vanadium, silicon, and/or boron) that areincorporated into the weld deposit formed using embodiments thedisclosed welding alloy and improve the mechanical properties of theweld deposit, despite the low manganese content. It may be noted,however, that the manganese content is considered when calculating thecarbon equivalence (CE) of a particular welding alloy embodiment, asdiscussed below.

In certain embodiments, the welding alloy may include less thanapproximately 2 wt % manganese (e.g., less than approximately 1.8 wt %,less than approximately 1.6 wt %, less than approximately 1.4 wt %, orless than approximately 1.2 wt % manganese). In certain embodiments, thewelding alloy may include less than approximately 1 wt % manganese(e.g., less than approximately 0.9 wt %, less than approximately 0.8 wt%, less than approximately 0.7 wt %, less than approximately 0.6 wt %,less than approximately 0.5 wt %, or less than approximately 0.4 wt %manganese). More specifically, as indicated in Table 1, in certainembodiments, the welding alloy may include between approximately 0.30 wt% and approximately 0.40 wt % manganese (e.g., approximately 0.38 wt %manganese or approximately 0.39 wt % manganese, as presented in Table 2)or between approximately 0.2 wt % and approximately 0.5 wt % manganese.In other embodiments, the manganese content of the welding alloy may befurther reduced, for example, to less than approximately 0.30 wt %, lessthan approximately 0.25 wt %, less than approximately 0.20 wt %, lessthan approximately 0.15 wt %, less than approximately 0.10 wt %, lessthan approximately 0.05 wt %, or to only trace levels. In certainembodiments, the manganese content of the welding alloy may be greaterthan approximately 0.1 wt %, greater than approximately 0.2 wt %, orgreater than approximately 0.3 wt %. In certain embodiments, the weldingalloy may be manufactured according to a particular target manganesecontent (e.g., 0.35 wt %), and the resulting welding alloy may have amanganese content that is approximately equal to the particular target,within a tolerance (e.g., ±25%, ±10%, or ±5%).

In certain embodiments, the manganese content within the welding alloymay be defined based on the desired tensile strength of a weld depositformed using the welding alloy. For example, in certain embodiments, thewelding alloy may include less than or equal to 0.9 wt % manganese andmay be capable of forming a weld deposit having a tensile strengthbetween approximately 70 kilopounds per square inch (ksi) and 90 ksi. Byfurther example, in certain embodiments, the welding alloy may includeless than or equal to 1.4 wt % manganese and may be capable of forming aweld deposit having a tensile strength between approximately 90 ksi and120 ksi.

Strengthening Agents

As mentioned above, the disclosed welding alloy may include one or morestrengthening agents to provide a weld deposit having suitablemechanical properties (e.g., tensile strength, toughness), despite thelower manganese content of the welding alloy. In certain embodiments,the one or more strengthening agents may include austenite stabilizers(e.g., nickel, carbon, copper, cobalt, etc.), which typically lower thetemperature of the solid phase transition from austenite to ferriteand/or raise the transition temperature from delta ferrite to austenite(e.g., retard the ferrite phase) during formation of the weld deposit.Additionally, in certain embodiments, the strengthening agents may,additionally or alternatively, include one or more of molybdenum,chromium, vanadium, silicon, and boron, which are not generallyconsidered to be austenite stabilizers, but may still improve mechanicalproperties (e.g., tensile strength, toughness) of the resulting welddeposit, in accordance with the present technique. It may be appreciatedthat the total, combined amount of strengthening agents present inwelding alloy embodiments may also be adjusted to provide a particularcarbon equivalency (CE) value or range, as discussed in detail below.

As presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0 wt % (i.e., none or traceamounts) and approximately 5 wt % nickel as a strengthening agent thatmay improve the mechanical properties of a weld deposit. In certainembodiments, the welding alloy may include between approximately 0.01 wt% and approximately 5 wt %, between approximately 0.2 wt % andapproximately 4 wt %, between approximately 0.3 wt % and approximately 3wt %, between approximately 0.4 wt % and approximately 2 wt %, orbetween approximately 0.5 wt % and approximately 1 wt % nickel. Morespecifically, in certain embodiments, the welding alloy may includebetween approximately 0.65 wt % and 0.85 wt % nickel (e.g.,approximately 0.76 wt % nickel or approximately 0.77 wt % nickel, aspresented in Table 2). Further, certain embodiments, the welding alloymay include between approximately 0.35 wt % and approximately 0.45 wt %or between approximately 1.75 wt % and approximately 2.75 wt % nickel.In certain embodiments, a nickel content of the welding alloy may begreater than approximately 0.01 wt %, greater than approximately 0.1 wt%, greater than approximately 0.15 wt %, greater than approximately 0.2wt %, less than approximately 5 wt %, less than approximately 0.01 wt %,or less than approximately 0.001 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0 wt % (i.e., none or traceamounts) and approximately 2 wt % cobalt as a strengthening agent thatmay improve the mechanical properties of a weld deposit. For example, incertain embodiments, the welding alloy may include between approximately0.01 wt % and approximately 2 wt %, between approximately 0.02 wt % andapproximately 1.5 wt %, between approximately 0.03 wt % andapproximately 1.0 wt %, between approximately 0.04 wt % andapproximately 0.8 wt %, or between approximately 0.05 wt % andapproximately 0.7 wt % cobalt. In certain embodiments, a cobalt contentof the welding alloy may be greater than approximately 0.01 wt %,greater than approximately 0.05 wt %, less than approximately 2 wt %,less than approximately 0.7 wt %, less than approximately 0.01 wt %, orless than approximately 0.001 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0.001 wt % and approximately 2wt % copper as a strengthening agent that may improve the mechanicalproperties of a weld deposit. For example, in certain embodiments, thewelding alloy may include between approximately 0.001 wt % andapproximately 0.7 wt %, between approximately 0.005 wt % andapproximately 0.4 wt %, or between approximately 0.01 wt % andapproximately 0.2 wt % copper (e.g., approximately 0.15 wt % copper orless than approximately 0.01 wt % copper, as presented in Table 2). Incertain embodiments, a copper content of the welding alloy may begreater than approximately 0.05 wt %, less than approximately 2 wt %,less than approximately 0.7 wt %, less than approximately 0.2 wt %, orless than approximately 0.01 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between 0.001 wt % and approximately 0.12 wt % carbonas a strengthening agent that may improve the mechanical properties of aweld deposit. More specifically, in certain embodiments, the weldingalloy may include between approximately 0.04 wt % and approximately 0.07wt %, or between approximately 0.05 wt % and approximately 0.06 wt %carbon (e.g., approximately 0.05 wt % carbon or approximately 0.052 wt %carbon, as presented in Table 2). In certain embodiments, a carboncontent of the welding alloy may be greater than approximately 0.001 wt%, greater than approximately 0.01 wt %, greater than approximately 0.04wt %, less than approximately 0.12 wt %, less than approximately 0.07 wt%, or less than approximately 0.06 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between 0 wt % (i.e., none or trace amounts) andapproximately 1.5 wt % molybdenum as a strengthening agent (i.e., anon-austenite strengthening agent) that may improve the mechanicalproperties of a weld deposit. For example, in certain embodiments, thewelding alloy may include between approximately 0.001 wt % andapproximately 1 wt % or between approximately 0.005 wt % andapproximately 0.5 wt % molybdenum (e.g., approximately 0.01 wt %molybdenum, as presented in Table 2). In certain embodiments, themolybdenum content of the welding alloy may be greater thanapproximately 0.001 wt %, greater than approximately 0.01 wt %, lessthan approximately 0.1 wt %, or less than approximately 1.5 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between 0 wt % (i.e., none or trace amounts) andapproximately 0.8 wt % chromium as a strengthening agent (i.e., anon-austenite strengthening agent) that may improve the mechanicalproperties of a weld deposit. For example, in certain embodiments, thewelding alloy may include between approximately 0.01 wt % andapproximately 0.8 wt % or between approximately 0.01 wt % andapproximately 0.2 wt % chromium (e.g., 0.01 wt % or 0.04 wt % chromium).In certain embodiments, the chromium content of the welding alloy may begreater than approximately 0.001 wt %, greater than approximately 0.01wt %, less than approximately 0.8 wt %, less than approximately 0.2 wt%, or less than approximately 0.1 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between 0 wt % (i.e., none or trace amounts) andapproximately 0.1 wt % vanadium as a strengthening agent (i.e., anon-austenite strengthening agent) that may improve the mechanicalproperties of a weld deposit. For example, in certain embodiments, thewelding alloy may include between approximately 0.0005 wt % andapproximately 0.09 wt % or between approximately 0.001 wt % andapproximately 0.025 wt % vanadium (e.g., approximately 0.006 wt %vanadium). In certain embodiments, a vanadium content of the weldingalloy may be greater than approximately 0.001 wt %, less thanapproximately 0.1 wt %, less than approximately 0.03 wt %, or less thanapproximately 0.001 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0.1 wt % and approximately 1.2wt % silicon. It may be noted that silicon may play more than one rolein the formulation of embodiments of the presently disclosed weldingalloy. For example, silicon may play a role as a deoxidizer, reactingwith oxygen-containing species at or near the weld pool to generateslag. However, the portion of silicon that persists in the weld depositmay also play a role as a strengthening agent (i.e., a non-austenitestrengthening agent) to improve the mechanical properties of a welddeposit. As such, the disclosed ranges of silicon in Table 1 include aportion of silicon that is consumed by deoxidation during welding, aswell as a portion of silicon that will become incorporated into the welddeposit as a strengthening agent. For example, in certain embodiments,the welding alloy may include between approximately 0.65 wt % andapproximately 0.85 wt % silicon (e.g., approximately 0.75 wt % siliconor approximately 0.79 wt % silicon, as presented in Table 2). In certainembodiments, the silicon content of the welding alloy may be greaterthan approximately 0.1 wt %, greater than approximately 0.65 wt %, lessthan approximately 0.85 wt %, or less than approximately 1.2 wt %.Silicon content is also discussed below with respect to deoxidizingcomponents of the disclosed welding alloy embodiments.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0 wt % (i.e., none or traceamounts) and approximately 0.01 wt % boron. That is, in certainembodiments, boron may not be included in welding alloy embodiments ofthe present approach without adversely affecting the properties of thewelding alloy and/or the resulting weld deposit. However, in certainembodiments, boron may be included in a small amount to improve themechanical properties of the resulting weld deposit. For example, incertain embodiments, the welding alloy may include between approximately0.0001 wt % and approximately 0.001 wt % boron (e.g., 0.0005 wt % boronor <0.001 wt % boron, as presented in Table 2). In certain embodiments,the boron content of the welding alloy may be greater than approximately0.0001 wt %, less than approximately 0.001 wt %, or less thanapproximately 0.01 wt %. It may be appreciated that boron may beconsidered both a strengthening agent and a grain control agent, asdiscussed herein. That is, the amount of boron present in a weldingalloy embodiment generally contributes to both the carbon equivalencevalue and to the total amount of grain control agents, as discussedbelow.

Carbon Equivalance (CE)

As mentioned above, welding alloy embodiments of the present approachgenerally include certain components, namely manganese and one or morestrengthening agents, at suitable levels to provide a particularequivalent carbon content value or range. For example, the disclosedwelding alloy embodiments have a particular carbon equivalent (CE) valueor range determined according to the Ito and Bessyo method (also knownas the critical metal parameter, Pcm) based on the following formula:CE=% C+% Si/30+(% Mn+% Cu+% Cr)/20+% Ni/60+% Mo/15+% V/10+5*% B  Eq. 1wherein each of the elemental percentages are provided in weight percentrelative to the total weight of the welding alloy. For example, incertain embodiments, the welding alloy may have a manganese content lessthan or equal to 2 wt % (e.g., less than approximately 1 wt % or between0.3 wt % and 0.4 wt % manganese) and a CE (determined according toequation 1) that is between approximately 0.05 and approximately 0.25.In certain embodiments, the welding alloy may have a CE (determinedaccording to equation 1) that is less than approximately 0.24, less thanapproximately 0.23, less than approximately 0.22, less thanapproximately 0.21, less than approximately 0.2, between approximately0.2 and approximately 0.23, or between approximately 0.08 andapproximately 0.23. In certain embodiments, the tubular welding wire 50may have a CE (determined according to equation 1) selected based on adesired tensile strength. For example, a welding alloy may have amanganese content less than approximately 2 wt % (e.g., less thanapproximately 1 wt % or between approximately 0.3 wt % and 0.4 wt %manganese) and have CE between approximately 0.2 and approximately 0.23to provide an estimated tensile strength between approximately 90 ksiand approximately 140 ksi (e.g., approximately 100 ksi). Otherembodiments designed to provide a lower estimated tensile strength(e.g., between approximately 70 ksi and approximately 80 ksi) may have amanganese content less than approximately 2 wt % (e.g., less thanapproximately 1 wt % or between approximately 0.3 wt % and 0.4 wt %manganese) and have a CE value below 0.2, such as between approximately0.07 and approximately 0.12.

Grain Control Agents

As presented in Table 1 above, the disclosed welding alloy embodimentsgenerally include one or more grain control agents that may improvemechanical properties (e.g., tensile strength, toughness) of theresulting weld deposit. In certain embodiments, these grain controlagents may include niobium, tantalum, titanium, zirconium, boron, andcombinations thereof. Accordingly, in certain embodiments, the weldingalloy may include between approximately 0.02 wt % and approximately 2.3wt %, between approximately 0.02 wt % and approximately 0.6 wt %,between approximately 0.05 wt % and approximately 0.7 wt %, or betweenapproximately 0.06 wt % and approximately 0.6 wt % combined graincontrol agents. In certain embodiments, the combined grain control agentcontent of the welding alloy may be greater than approximately 0.02 wt%, greater than approximately 0.06 wt %, less than approximately 0.6 wt%, or less than approximately 0.56 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0 wt % (i.e., none or traceamounts) and approximately 0.1 wt % niobium as a grain control agentthat may improve the mechanical properties of the weld deposit. Forexample, in certain embodiments, the welding alloy may include betweenapproximately 0.001 wt % and approximately 0.1 wt %, betweenapproximately 0.005 wt % and approximately 0.09 wt %, or betweenapproximately 0.01 wt % and approximately 0.08 wt % niobium. In certainembodiments, the niobium content of the welding alloy may be greaterthan approximately 0.001 wt %, less than approximately 0.15 wt %, lessthan approximately 0.12 wt %, or less than approximately 0.1 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0 wt % (i.e., none or traceamounts) and approximately 0.2 wt % tantalum as a grain control agent toimprove the mechanical properties of the weld deposit. For example, incertain embodiments, the welding alloy may include between approximately0.001 wt % and approximately 0.2 wt %, between approximately 0.005 wt %and approximately 0.15 wt %, or between approximately 0.01 wt % andapproximately 0.1 wt % tantalum. In certain embodiments, a tantalumcontent of the welding alloy may be greater than approximately 0.001 wt%, less than approximately 0.2 wt %, or less than approximately 0.1 wt%.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0.01 wt % and approximately 0.2wt % titanium. It may be noted that, like silicon discussed above,titanium may play more than one role in the welding operation. Forexample, titanium may play a role as a deoxidizer, reacting withoxygen-containing species near the weld pool to generate slag, asdiscussed below. However, the titanium that persists in the weld depositmay also play a role as a grain control agent that may improve themechanical properties of the weld deposit. As such, the disclosed rangesof titanium in Table 1 include the titanium that will be consumed bydeoxidation (e.g., approximately 60%), as well as the titanium that willbecome incorporated into the weld deposit during welding. For example,in certain embodiments, the welding alloy may include betweenapproximately 0.01 wt % and approximately 0.18 wt %, betweenapproximately 0.04 wt % and approximately 0.16 wt %, or betweenapproximately 0.08 wt % and approximately 0.12 wt % titanium. In certainembodiments, a titanium content of the welding alloy may be greater thanapproximately 0.01 wt %, greater than approximately 0.08 wt %, less thanapproximately 0.2 wt %, or less than approximately 0.16 wt %.

As also presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0.01 wt % and approximately 0.2wt % zirconium. It may be noted that, like titanium, zirconium may playmore than one role in the welding operation. For example, zirconium mayplay a role as a deoxidizer, reacting with oxygen-containing speciesnear the weld pool to generate slag, as discussed below. However, thezirconium that persists in the weld deposit after welding may also serveas a grain control agent that may improve the mechanical properties ofthe weld deposit. As such, the disclosed ranges of zirconium in Table 1include the portion of zirconium that will be consumed by deoxidation(e.g., approximately 60%), as well as the portion zirconium that willbecome incorporated into the weld deposit, during welding. For example,in certain embodiments, the welding alloy may include betweenapproximately 0.01 wt % and approximately 0.15 wt % or betweenapproximately 0.02 wt % and approximately 0.1 wt % zirconium. In certainembodiments, a zirconium content of the welding alloy may be greaterthan approximately 0.01 wt %, greater than approximately 0.02 wt %,greater than approximately 0.04 wt %, less than approximately 0.1 wt %,less than approximately 0.08 wt %, or less than approximately 0.02 wt %.

As mentioned above, the amount of boron present a welding alloyembodiment generally contributes both the carbon equivalence (CE) valueand to the total amount of grain control agents present in the weldingalloy. As presented in Table 1, the disclosed welding alloy embodimentsgenerally include between approximately 0 wt % (i.e., none or traceamounts) and approximately 0.01 wt % boron. For example, in certainembodiments, the welding alloy may include between approximately 0.0001wt % and approximately 0.001 wt % boron (e.g., 0.0005 wt % boron or<0.001 wt % boron, as presented in Table 2). In certain embodiments, theboron content of the welding alloy may be greater than approximately0.0001 wt %, less than approximately 0.001 wt %, or less thanapproximately 0.01 wt %.

Other Components

Further, as presented in Table 1, in certain embodiments, the solidwelding alloy may include deoxidizing components (e.g., titanium,zirconium, aluminum, and silicon) in the indicated ranges. As set forthabove, certain deoxidizing components may also serve other roles (e.g.,strengthening agents, grain control agents), and these components may bepresent at levels that enable a suitable portion of these components tobecome incorporated into the weld deposit to provide these effects. Incertain embodiments, antimony may not be included without adverselyaffecting the present approach; while in other embodiments, antimony(e.g., up to 0.25 wt %) may be useful to tune the properties of theresulting weld deposit. In certain embodiments, the disclosed weldingalloy embodiments may include greater than approximately 80 wt % iron(e.g., greater than approximately 83 wt %, greater than approximately 84wt %, greater than approximately 90 wt %, greater than approximately 95wt %, greater than approximately 96 wt %, greater than approximately 97wt %, greater than approximately 98 wt %, greater than approximately 99wt % iron, or a remainder of iron).

AWS Standards and Classification

Certain welding electrodes (e.g., welding electrodes manufacturedaccording to the American Welding Society (AWS) A5.18 ER70S-2 standard)for welding structural steels include between 0.9 wt % and 1.4 wt %manganese. By comparison, the ER70S-2 wire contains betweenapproximately 2 and approximately 5 times greater manganese content thancertain welding alloy embodiments of the present approach, such as awelding alloy embodiment having between approximately 0.3 wt % andapproximately 0.4 wt % manganese. Further, based on the AWSspecification, the ER70S-2 wire includes less than or equal to 0.15 wt %nickel. By comparison, certain embodiments of the present approach(e.g., embodiments of the subclass A2 and A3 of Table 1) may containbetween approximately 4 and approximately 6 times greater nickel contentthan the ER70S-2 wire. For example, in certain embodiments, thedisclosed welding alloy may include less than approximately 1 wt %manganese (e.g., less than or equal to approximately 0.9 wt % manganese,less than approximately 0.4 wt % manganese) and greater thanapproximately 0.15 wt % nickel (e.g., greater than approximately 0.16 wt%, greater than approximately 0.18 wt %, greater than approximately 0.2wt %, greater than approximately 0.25 wt %, or greater thanapproximately 0.75 wt % nickel).

It may be appreciated that the formulations in Tables 1 and 2 are merelyprovided as example formulations. In certain embodiments, the presentlydisclosed low-manganese welding alloy may be used to produce a weldingconsumable (e.g., a solid welding wire, a stick electrode, or a tubularwelding wire) in compliance with the chemical analysis requirements ofone or more of the following AWS A5.29, A5.20, and/or A5.36 standards:E71T1-GC H8 (e.g., providing similar weld deposit chemistry andmechanical properties as Element™ 71Ni1C, available from Hobart BrothersCompany, Troy, Ohio); E71T1-GM H8 (e.g., providing similar weld depositchemistry and mechanical properties as Element™ 71Ni1M, available fromHobart Brothers Company, Troy, Ohio); E71T-1C H8 (e.g., providingsimilar weld deposit chemistry and mechanical properties as Element™71T1C, available from Hobart Brothers Company, Troy, Ohio); E71T-1M H8(e.g., providing similar weld deposit chemistry and mechanicalproperties as Element™ 71T1M, available from Hobart Brothers Company,Troy, Ohio); E81T1-GC H8 (e.g., providing similar weld deposit chemistryand mechanical properties as Element™ 81K2C, available from HobartBrothers Company, Troy, Ohio); and E81T1-GM H8 (e.g., providing similarweld deposit chemistry and mechanical properties as Element™ 81K2M,available from Hobart Brothers Company, Troy, Ohio).

Manufacturing the Welding Alloy and Welding Consumables

The disclosed welding consumables, including solid welding electrodes,may be formed from a mixture of starting materials or ingredients thatmay be formed into an alloy using common steel manufacturing processesand techniques. For example, these starting materials may include iron,iron titanium powder, iron zirconium powder, aluminum powder or alumina,as well as other suitable starting materials. For example, in certainembodiments, the starting materials may include one or more materials(e.g., antimony, gallium) set forth in the U.S. Pat. Nos. 6,608,284 and8,119,951, both of which are incorporated by reference herein in theirentireties for all purposes. In general, the various starting materialsmay be heated within a furnace to reach a molten state. Additionally,one or more impurities (e.g., oxides of titanium, zirconium, aluminum,and/or silicon) may be removed from the mixture as slag. Accordingly,after a portion of certain starting materials are oxidized and removedas slag during formation of the welding alloy, the composition of theresulting welding alloy complies with the component ranges for one ormore of the classes A1, A2, and A3 indicated in Table 1. Once formed, incertain embodiments, the welding alloy may be shaped into welding wire(as discussed below), into ribbons (e.g., strip cladding for use instrip welding operations), into bars or plates, or any other type ofwelding consumable used in a welding operation.

In certain embodiments, the welding alloy may be drawn (e.g., using oneor more drawing dies) to form a solid wire (e.g., for use in GMAW, GTAW,and SAW applications). Additionally, in certain embodiments, the solidwire may be cut into segments and covered with a coating to producestick electrodes. Further, in certain embodiments, the welding alloy maybe flattened, shaped into a sheath, and filled with a granular corematerial (e.g., flux) to produce a metal-cored or a flux-cored tubularwelding wire. Even further, in certain embodiments, the welding alloymay be disposed on a workpiece and applied via a plating process. It maybe appreciated that, for embodiments of welding consumables that includea flux and/or a coating component (e.g., stick electrodes and/orflux-cored tubular welding wire), the chemistry of the weld deposit, themechanical properties of the weld deposit, the properties of the arc,and so forth, may be also controlled or tuned based on the compositionand nature of the flux and/or coating component. In particular, incertain embodiments, the flux and/or coatings used in combination withthe disclosed welding alloys (e.g., for SMAW stick electrodes, withinflux-cored electrodes, and for SAW flux) may be substantially free orcompletely free from manganese.

By specific example, in certain embodiments, the disclosed alloys may beused to manufacture SMAW stick electrodes. In an example, a solid wiremay be manufactured from the disclosed welding alloys, cut intosegments, and coated with flux to produce stick electrodes suitable forSMAW. In this example, the presently disclosed welding alloys enable thedelivery of the aforementioned deoxidizers (e.g., zirconium, titanium,aluminum, and/or silicon) to the arc and/or the weld deposit. In certainembodiments, the SMAW stick electrode may be in compliance with the AWSA5.1 or AWS A5.5 (e.g., classified as an Exx18 or an Exx18-Y electrode)and may have a flux coating that is completely free or substantiallyfree from manganese. In certain embodiments, the solid wire segments maybe first coated with another metal (e.g., a deposited metal layer or ametal foil) prior to the application of the flux coating to improveadhesion of the flux coating and/or to limit interaction between certainflux components and the solid wire core. In certain embodiments, theflux coating may be basic (e.g., contributes minimal oxygen to the welddeposit) and may include silicon metal powders that are stabilized(e.g., chromated) prior to use.

As mentioned, in certain embodiments, the welding alloy may be drawn toform a solid wire for use in GMAW, GTAW, and SAW applications.Additionally, in certain embodiments, the solid welding wire may becoated with one or more components to facilitate one or more aspects ofthe welding process. For example, in certain embodiments, the solidwelding wire may be manufactured to include a thin copper coating tofacilitate feeding of the welding wire. In certain embodiments, thiscopper coating may be formed electrolytically or via self-deposition ina vacuum. For embodiments that include this copper coating, thecomposition of the welding alloy may be adjusted such that thecomposition of the entire welding electrode (including the coating)falls within the disclosed ranges for the disclosed welding alloys(e.g., A1, A2, and/or A3 of Table 1). Furthermore, in certainembodiments, in addition or in alternative to a copper coating, thesolid welding wire may include a lubricant (e.g., an oil-based) coatingto further facilitate the feeding of the welding wire. Additionally, incertain embodiments, this lubricant coating may include one or moreGroup I or Group II compounds (e.g., sodium, potassium, lithium,magnesium, calcium, and/or barium salts) that may provide the solidwelding wire with arc stabilizing effects during an arc weldingoperation.

Weld Deposit

Table 3 illustrates an expected chemical composition and mechanicalproperties for weld deposits formed using the solid welding electrodeembodiments E1 and E2 of Table 2, which are example welding consumablesmanufactured from the disclosed welding alloys (e.g., welding alloys A1,A2, or A3 of Table 1). As set forth in Table 3, in certain embodiments,the resulting weld deposits may include less than or equal to 1 wt %manganese (e.g., between approximately 0.3 wt % and approximately 0.4 wt% manganese). In certain embodiments, the weld deposit may include lessthan approximately 1.25 wt %, less than approximately 1 wt %, less thanapproximately 0.9 wt %, less than approximately 0.8 wt %, less thanapproximately 0.7 wt %, less than approximately 0.6 wt %, less thanapproximately 0.5 wt %, less than approximately 0.4 wt %, less thanapproximately 0.3 wt %, less than approximately 0.2 wt %, less thanapproximately 0.1 wt %, or only trace amounts of manganese, based on themanganese content of the welding alloy used to form the weld deposit.

TABLE 3 Chemical composition (wt %) and mechanical properties forexample weld deposits W1, W2, and W3 formed using the solid weldingelectrode embodiment E1 of Table 2, and weld deposit W4, W5, and W6formed using the solid welding electrode embodiment E2 of Table 2,deposited on an A36 base plate. Mechanical properties are determinedaccording to AWS A5.18. The “90/10” shielding gas mixture isapproximately 90% argon and approximately 10% CO₂. All of the welddeposits are formed in a 1 g position using a solid wire having adiameter of 0.045 inches. W1 W2 W3 W4 W5 W6 Carbon 0.068 0.065 0.0680.077 0.083 0.067 Manganese 0.304 0.375 0.361 0.344 0.335 0.28 Silicon0.485 0.528 0.543 0.541 0.503 0.343 Phosphorus 0.004 0.006 0.005 0.0050.004 0.005 Sulfur 0.009 0.011 0.01 0.007 0.006 0.006 Nickel 0.735 0.6320.646 0.665 0.651 0.671 Chromium 0.03 0.029 0.027 0.021 0.024 0.027Molybdenum 0.008 0.009 0.009 0.007 0.01 0.006 Vanadium 0.001 0.002 0.0010.003 0.002 0.001 Copper 0.073 0.11 0.086 0.247 0.255 0.224 Titanium0.046 0.043 0.053 0.042 0.034 0.021 Zirconium 0.01 0.01 0.015 0.0090.007 0.003 Aluminum 0.031 0.032 0.038 0.009 0.006 0.003 Boron 0.00010.00011 0.0001 0.0001 0.00016 0.0001 Niobium 0.001 0.001 0.001 0.0010.001 0.001 Oxygen 0.074 0.07 0.053 0.055 0.064 0.097 Nitrogen 0.0040.0037 0.0039 0.0039 0.005 0.0062 Carbon 0.12 0.12 0.12 0.14 0.14 0.12Equivalance (CE) Shielding Gas CO₂ CO₂ 90/10 CO₂ CO₂ CO₂ Yield strength67.6 64.1 77.4 61.4 63.7 59.9 (ksi) Tensile strength 77.6 74.6 87.8 76.876.7 72.4 (ksi) Elongation 26 27.6 20.5 25.1 22.6 26.4 (% in 2″) AreaReduction % 62.1 67.8 47.7 58.1 50.5 59.9 CVN (ft-lbs) at 70.8 54.8 2293.4 36.4 34.6 −20° F.

As indicated in Table 3, the example weld deposits formed using thedisclosed welding alloys include one or more strengthening agents (e.g.,nickel, copper, carbon, molybdenum, chromium, vanadium, silicon, and/orboron) and one or more grain control agents (e.g., niobium, tantalum,titanium, and/or zirconium) at particular concentrations that enable theweld deposit to have suitable mechanical properties, despite the lowermanganese content. It may be appreciated that, for certain weldingoperations, such as a TIG welding operation using 100% argon as ashielding gas and a filler rod of the presently disclosed welding alloy,the chemistry of the weld deposit may be substantially the same as thechemistry of the welding alloy, as described in detail above. Forexample, for certain welding operations, the weld deposit may fallwithin the ranges defined by the classes A1, A2, or A3 of Table 1, andmay include any of the ranges for strengthening agents, grain controlagents, carbon equivalency (CE), etc., set forth above for the weldingalloy. For other welding operations, such as the GTAW operations used toform the weld deposits W1, W2, W3, W4, and W5 of Table 3, the amounts ofone or more components may be altered (e.g., by the chemistry of thebase metal or by oxidization), and may therefore be different than thelevels of these components in the welding consumable made from thedisclosed welding alloy. For example, in certain embodiments, a welddeposit formed using a welding consumable that is an embodiment of thepresently disclosed welding alloy may include: a carbon content that isless than approximately 0.12 wt % (e.g., less than approximately 0.07 wt% carbon); a manganese content that is less than approximately 2 wt %(e.g., less than approximately 1 wt %, less than approximately 0.9 wt %,or between approximately 0.3 wt % and approximately 0.4 wt % manganese);a silicon content that is less than approximately 1.2 wt % (e.g., lessthan approximately 0.6 wt % silicon); a nickel content that is less thanapproximately 5 wt % (e.g., less than approximately 1 wt %, less thanapproximately 0.85 wt % nickel); a chromium content that is less thanapproximately 0.8 wt % (e.g., less than approximately 0.4 wt %chromium); a molybdenum content that is less than approximately 1.5 wt %(e.g., less than approximately 0.01 wt % molybdenum); a vanadium contentthat is less than approximately 0.1 wt % (e.g., less than approximately0.03 wt % vanadium); a copper content that is less than approximately 2wt % (e.g., less than approximately 0.2 wt % copper); a titanium contentthat is less than approximately 0.2 wt % (e.g., less than approximately0.06 wt % titanium); a zirconium content that is less than approximately0.2 wt % zirconium (e.g., less than approximately 0.02 wt % zirconium);an aluminum content less than approximately 1 wt % (e.g., less thanapproximately 0.04 wt % aluminum); a boron content less thanapproximately 0.01 w t % (e.g., less than approximately 0.0002 wt %boron); a niobium content that is less than approximately 0.1 wt %(e.g., less than approximately 0.002 wt % niobium); and/or a tantalumcontent that is less than approximately 0.1 wt % (e.g., less thanapproximately 0.001 wt % tantalum).

Additionally, Table 3 illustrates examples of the mechanical propertiesenabled by the presently disclosed welding alloy embodiments, despitethe lower manganese content. For example, as presented in Table 3, welddeposits formed using an embodiment of the disclosed welding alloygenerally possess a tensile strength that is greater than or equal to 70ksi, despite having a low manganese content (e.g., less than 1 wt %manganese). In certain embodiments, the weld deposit may have a highertensile strength, such as between approximately 70 ksi and 80 ksi,between approximately 80 ksi and 90 ksi, between approximately 90 ksiand 100 ksi, or between approximately 100 ksi and 140 ksi. Additionally,as presented in Table 3, weld deposits formed using an embodiment of thedisclosed welding alloy generally possess a yield strength that isgreater than or equal to 58 ksi. In certain embodiments, the welddeposit may have a higher yield strength, such as between approximately58 ksi and approximately 75 ksi. Further, as presented in Table 3, welddeposits formed using an embodiment of the disclosed welding alloygenerally possess a Charpy V-notch (CVN) value that is greater than orequal to 20 foot pounds (ft-lbs) at −20° F. In certain embodiments, theweld deposit may have a higher CVN value, such as greater than 30ft-lbs, greater than 40 ft-lbs, greater than 50 ft-lbs, greater than 60ft-lbs, or greater than 70 ft-lbs.

Welding Fumes

Table 4 includes welding fume data for a series of gas metal arc welding(GMAW) operations using an embodiment of a solid welding wiremanufactured from the disclosed A3 welding alloy. The welding fume dataof Table 4 is also presented visually in the graphs of FIGS. 2, 3, 4, 5,and 6 . While the data of Table 4 and FIGS. 2-6 has been generated usinga specific welding consumable embodiment (e.g., E2 solid welding wire ofTable 2) of a specific disclosed type of welding alloy (e.g., A3 weldingalloy of Table 1), it is believed that the welding fume data presentedin Table 4 is representative of other embodiments of welding consumablesgenerally falling within the compositional ranges of the Al weldingalloy of Table 1. Further, while the data of Table 4 was generated usinga gas metal arc welding (GMAW) operation, it is believed that the fumedata presented in Table 4 is representative of the welding fume data ofother welding operations (e.g., submerged arc welding (SAW), shieldedmetal arc welding (SMAW), or gas tungsten arc welding (GTAW)operations).

TABLE 4 Welding fume data for a series of example welding operationsusing an embodiment of a solid welding wire made from the disclosed A3welding alloy (e.g., an embodiment of the disclosed E2 solid weldingwire). All welding operations were performed using a 90% argon/10% CO₂shielding gas mixture. Fume testing was performed in accordance with AWSF1.2 using a bead-on-plate in a horizontal (1F) position with anelectrical stick-out of between approximately 0.5 inches andapproximately 0.75 inches and a wire diameter of 0.045 inches. Wire FumeMn Fume Feed Melt- Generation Mn Generation Welding Speed Current BiasOff Rate Electrode in Rate Electrode (in/min) (A) (V) (lbs/hr) (g/min)to fumes fumes (g/min) A3 100 110 21 6.8036 0.134 0.65% 2.50% 0.00334250 225 27 6.8036 0.283 0.55% 1.60% 0.00453 300 250 28 8.1632 0.2840.46% 1.80% 0.00511 355 280 29 9.6558 0.434 0.59% 1.30% 0.00564 425 30030 11.5688 0.332 0.54% 1.50% 0.00498 500 335 31 13.6038 0.122 0.12%2.20% 0.00268 700 425 32 19.0382 0.101 0.07% 6.40% 0.00644

As illustrated by the curve 40 of FIG. 2 and the curve 42 of FIG. 3 ,respectively, the A3 solid welding electrode embodiment provides anearly linear trend between the melt-off rate and the welding currentand between the melt-off rate and the wire feed speed (i.e., the rate ofadvancement of the welding consumable toward the workpiece). Asillustrated by the curve 44 of FIG. 4 , the A3 solid welding electrodeembodiment has a similar percentage of the welding electrode convertedto fumes at wire feed speeds between approximately 250 and approximately425 inches per minute, a slightly higher percentage of the weldingelectrode converted to fumes at wire feed speeds less than approximately250 inches per minute, and substantially lower percentages of thewelding electrode converted to fumes at wire feed speeds greater thanapproximately 425 inches per minute. As illustrated by the curve 46 ofFIG. 5 , the A3 solid welding electrode embodiment has a similar fumegeneration rate at wire feed speeds of approximately 250, approximately300, and approximately 425 inches per minute, a highest fume generationrate at a wire feed speed of approximately 350 inches per minute, andsubstantially lower fume generation rate at wire feed speeds less thanapproximately 200 inches per minute and at wire feed speeds greater thanapproximately 500 inches per minute.

As illustrated by the curve 48 of FIG. 6 , the A3 solid weldingelectrode embodiment provides a low manganese fume generation rate atall wire feed speeds (e.g., between 100 and 700 inches per minute). Incertain embodiments, the manganese fume generation rate provided by anembodiment of the disclosed Al welding alloy (e.g., the A3 solid weldingelectrode of Table 4) may be less than approximately 0.01 grams perminute, less than approximately 0.009 grams per minute, less thanapproximately 0.008 grams per minute, less than approximately 0.007grams per minute, less than approximately 0.0065 grams per minute, lessthan approximately 0.006 grams per minute, less than approximately 0.005grams per minute, less than approximately 0.004 grams per minute, orless than approximately 0.003 grams per minute during an arc weldingoperation, depending on the parameters (e.g., wire feed speed, current,voltage, etc.) of the welding operation. In certain embodiments, themanganese fume generation rate provided by an embodiment of thedisclosed A1 welding alloy (e.g., the A3 solid welding electrode ofTable 4) may be between approximately 0.001 and approximately 0.01 gramsper minute, between approximately 0.002 and approximately 0.007 gramsper minute, or between approximately 0.0025 and approximately 0.0065grams per minute.

While only certain features of the disclosure have been illustrated anddescribed herein, many modifications and changes will occur to thoseskilled in the art. It is, therefore, to be understood that the appendedclaims are intended to cover all such modifications and changes as fallwithin the scope of the claims.

We claim:
 1. An arc welding consumable that forms a weld deposit on asteel workpiece during an arc welding operation, wherein the weldingconsumable comprises: less than 0.4 wt % manganese; strengthening agentsselected from the group consisting of nickel, cobalt, copper, carbon,molybdenum, chromium, vanadium, silicon, and boron, where thestrengthening agents include: between 0.001 wt % and 1.0 wt %molybdenum; and grain control agents selected from the group consistingof niobium, tantalum, titanium, zirconium, and boron, wherein the graincontrol agents comprise greater than 0.06 wt % and less than 0.6 wt % ofthe welding consumable, wherein the weld deposit comprises a tensilestrength greater than or equal to 70 ksi, a yield strength greater thanor equal to 58 ksi, a ductility, as measured by percent elongation, thatis at least 22%, and a Charpy V-notch toughness greater than or equal to20 ft-lbs at −20° F., and wherein the welding consumable provides amanganese fume generation rate less than 0.01 grams per minute duringthe arc welding operation.
 2. The welding consumable of claim 1, whereinthe manganese fume generation rate is less than 0.007 grams per minuteduring the arc welding operation.
 3. The welding consumable of claim 1,wherein the manganese fume generation rate is less than 0.006 grams perminute during the arc welding operation.
 4. The welding consumable ofclaim 1, wherein the manganese fume generation rate is between 0.0025grams per minute and 0.0065 grams per minute when a rate of advancementof the welding consumable toward a workpiece is less than 700 inches perminute, or when a welding current is less than 425 amps, or both, duringthe arc welding operation.
 5. The welding consumable of claim 1, whereinthe welding consumable comprises a solid welding wire, a filler rod, ora stick electrode, and wherein the arc welding operation comprises a gasmetal arc welding (GMAW) operation, a submerged arc welding (SAW)operation, a shielded metal arc welding (SMAW) operation, or a gastungsten arc welding (GTAW) operation.
 6. The welding consumable ofclaim 1, wherein the welding consumable comprises between 0.3 wt % and0.4 wt % manganese.
 7. The welding consumable of claim 1, wherein thestrengthening agents comprise copper, and wherein the welding consumablecomprises between 0.001 wt % and 2 wt % copper.
 8. The weldingconsumable of claim 1, wherein the strengthening agents comprise carbon,and wherein the welding consumable comprises between 0.001 wt % and 0.12wt % carbon.
 9. The welding consumable of claim 1, wherein thestrengthening agents comprise chromium, and wherein the weldingconsumable comprises between 0.001 wt % and 0.8 wt % chromium.
 10. Thewelding consumable of claim 1, wherein the grain control agents comprisetitanium, and wherein the welding consumable comprises between 0.01 wt %and 0.2 wt % titanium.
 11. The welding consumable of claim 1, whereinthe grain control agents comprise zirconium, and wherein the weldingconsumable comprises between 0.01 wt % and 0.2 wt % zirconium.
 12. Thewelding consumable of claim 1, wherein the strengthening agents and theone or more grain control agents comprise boron, and wherein the weldingconsumable comprises between 0.0001 wt % and 0.01 wt % boron.
 13. Thewelding consumable of claim 1, wherein the welding consumables has acarbon equivalence (CE) of between 0.07 and 0.2 as determined accordingto Ito and Bessyo's method.
 14. The welding consumable of claim 1,wherein the welding consumable comprises a metal sheath and a granularcore.
 15. The welding consumable of claim 1, wherein the weldingconsumable is a solid wire.
 16. The welding consumable of claim 1,wherein the manganese fume generation rate is less than 0.01 grams perminute during the arc welding operation.
 17. The welding consumable ofclaim 1, wherein the strengthening agents comprise nickel, and whereinthe welding consumable comprises between 0.65 wt % and 0.85 wt % nickel.18. The welding consumable of claim 1, wherein the strengthening agentscomprise cobalt, and wherein the welding consumable comprises between0.05 wt % and 0.7 wt % cobalt.
 19. The welding consumable of claim 1,wherein the strengthening agents comprise vanadium, and wherein thewelding consumable comprises between 0.001 wt % and 0.025 wt % vanadium.20. The welding consumable of claim 1, wherein the strengthening agentsinclude between 0.1 and 1.2 wt % silicon.